PIC17C7XX Datasheet, PDF (259/328 Pages) Microchip Technology – High-Performance 8-Bit CMOS EPROM Microcontrollers with 10-bit A/D

PIC17C7XX
FIGURE 20-17: USART ASYNCHRONOUS MODE START BIT DETECT
RX
(RX/DT pin)
x16 CLK
121A
Start bit
Q2, Q4 CLK
120A
123A
TABLE 20-17: USART ASYNCHRONOUS MODE START BIT DETECT REQUIREMENTS
Param
No. Sym
Characteristic
Min
120A TdtL2ckH Time to ensure that the RX pin is sampled low
—
121A TdtRF
Data rise time and fall time
Receive
—
Transmit
—
123A ^{TckH2bckL Time from RX pin sampled low to first rising edge}
—
of x16 clock
† These parameters are for design guidance only and are not tested.
§ This specification ensured by design.
Note 1: Schmitt trigger will determine logic level.
Typ† Max Units
— TCY § ns
— Note 1 ns
— 40 † ns
— TCY § ns
Conditions
FIGURE 20-18: USART ASYNCHRONOUS RECEIVE SAMPLING WAVEFORM
RX
(RX/DT pin)
baud CLK
Start bit
Bit0
Baud CLK for all but start bit
x16 CLK
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2 3
125A
126A
Samples
TABLE 20-18: USART ASYNCHRONOUS RECEIVE SAMPLING REQUIREMENTS
Param
No.
Sym
Characteristic
Typ
Min
†
Max Units
125A
TdtL2ckH Setup time of RX pin to first data sam- TCY § —
—
ns
pled
126A
TdtL2ckH Hold time of RX pin from last data sam- TCY § —
—
ns
pled
§ This specification ensured by design.
Conditions
© 1998 Microchip Technology Inc.
Preliminary
DS30289A-page 259